Main ride operator Peter Nemeth will continue giving evidence to the inquest into the deaths of Cindy Low, Kate Goodchild, her brother Luke Dorsett and his partner Roozi Araghi when the inquest resumes at Southport.

On Tuesday, Mr Nemeth told the inquest he'd noticed the raft carrying the guests on a collision course to a stricken raft following a water pump malfunction.

Despite pushing a button to stop the ride's conveyor "two or three times", the attraction did not immediately shut down and the two rafts collided.

The four victims were killed instantly after being thrown from the raft into the conveyor mechanism.

Ms Goodchild's 12-year-old daughter and Ms Low's 10-year-old son survived the accident.

Mr Nemeth, who said he was among the "top 10" operators in the theme park, was unaware the button he pressed did not bring the conveyor to an immediate halt.

Instead a police investigation revealed it took up to nine seconds for the ride to stop.

"I am surprised to learn that," Mr Nemeth said.

"I assumed the conveyor stop button would stop the ride instantly."

The ride's water pump had failed twice already on the day of the tragedy and Mr Nemeth had been informed to shut down the ride if it happened again.

He said he did not know that was a park policy until that day and had been operating other rides in the past where up to six malfunctions had happened and the ride continued to take guests.

"It was a regular occurrence," he said, adding he had been working on the Thunder River Rapids ride a week before the tragedy when the pump had failed.

The other ride operator at the time of the tragedy, Courtney Williams, is also expected to give evidence on Wednesday.

The inquest heard on Tuesday Ms Williams had only been trained on her role for the attraction on the morning of the tragedy.

The inquest resumes at 10am.

Australian Associated Press